U.S. Pat. No. 4,029,549 discloses and claims the use of Mycobacterium fortuitum NRRL B-8119 to make 9-hydroxy-3-oxo-4-pregnene-20-carboxylic acid [9-hydroxybisnoracid]. The same microbe is used to make 9-hydroxy-4-androstene-3,17-dione [9-hydroxyandrostenedione] in U.S. Pat. No. 4,035,236; and 9-hydroxy-3-oxo-4-pregnene-20-carboxylic acid methyl ester [9-hydroxybisnoracid methyl ester] in U.S. Pat. No. 4,214,051.
European Patent Application 79104372.2 discloses a two-stage fermentation for preparing 9-hydroxy-3-oxo-4,17(20)-pregnadiene-20-carboxylic acid (I) which is useful as an intermediate in the synthesis of valuable corticoids. This process entails first the conversion of sterols to 3-oxo-4,17(20)-pregnadiene-20-carboxylic acid by fermentation with Mycobacterium strain NRRL B-8054, and then conversion of this compound to (I) by incubation with any one of several microorganisms capable of introducing a hydroxyl group in the 9.alpha. position.